Cold plugged USB device was not detected on certain PCIe USB cards
(like Inateck card connected to AM64 EVM or connected to J7200 EVM).
Re-plugging the USB device always gets it enumerated.
This issue was discussed in
https://lore.kernel.org/r/[email protected]
and
https://bugzilla.kernel.org/show_bug.cgi?id=214021
So the suggested solution is to register both root hubs along with the
second hcd for xhci.
RFC Patch series can be found at [1]
v1 Patch series can be found at [3]
Changes from RFC:
1) Mathias identified potential issues with the RFC patch [2] and suggested
the solution to use HCD flags. This series implements it.
Changes from v1:
1) Fixed code comments pointed out by Alan Stern
2) Renamed the HCD flag variable to "HCD_FLAG_DEFER_RH_REGISTER" from
"HCD_FLAG_DEFER_PRI_RH_REGISTER"
[1] -> https://lore.kernel.org/linux-usb/[email protected]/
[2] -> https://lore.kernel.org/linux-usb/[email protected]
[3] -> https://lore.kernel.org/r/[email protected]
Kishon Vijay Abraham I (3):
usb: core: hcd: Modularize HCD stop configuration in usb_stop_hcd()
usb: core: hcd: Add support for deferring roothub registration
xhci: Set HCD flag to defer primary roothub registration
drivers/usb/core/hcd.c | 66 +++++++++++++++++++++++++++--------------
drivers/usb/host/xhci.c | 1 +
include/linux/usb/hcd.h | 2 ++
3 files changed, 47 insertions(+), 22 deletions(-)
--
2.17.1
It has been observed with certain PCIe USB cards (like Inateck connected
to AM64 EVM or J7200 EVM) that as soon as the primary roothub is
registered, port status change is handled even before xHC is running
leading to cold plug USB devices not detected. For such cases, registering
both the root hubs along with the second HCD is required. Add support for
deferring roothub registration in usb_add_hcd(), so that both primary and
secondary roothubs are registered along with the second HCD.
Signed-off-by: Kishon Vijay Abraham I <[email protected]>
Suggested-by: Mathias Nyman <[email protected]>
Tested-by: Chris Chiu <[email protected]>
---
drivers/usb/core/hcd.c | 27 ++++++++++++++++++++++-----
include/linux/usb/hcd.h | 2 ++
2 files changed, 24 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 00d35fe1fef0..64fdfc6692c2 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2795,6 +2795,7 @@ int usb_add_hcd(struct usb_hcd *hcd,
{
int retval;
struct usb_device *rhdev;
+ struct usb_hcd *shared_hcd;
if (!hcd->skip_phy_initialization && usb_hcd_is_primary_hcd(hcd)) {
hcd->phy_roothub = usb_phy_roothub_alloc(hcd->self.sysdev);
@@ -2955,18 +2956,34 @@ int usb_add_hcd(struct usb_hcd *hcd,
goto err_hcd_driver_start;
}
+ /* starting here, usbcore will pay attention to the shared HCD roothub */
+ shared_hcd = hcd->shared_hcd;
+ if (!usb_hcd_is_primary_hcd(hcd) && shared_hcd && HCD_DEFER_RH_REGISTER(shared_hcd)) {
+ retval = register_root_hub(shared_hcd);
+ if (retval != 0)
+ goto err_register_shared_root_hub;
+
+ if (shared_hcd->uses_new_polling && HCD_POLL_RH(shared_hcd))
+ usb_hcd_poll_rh_status(shared_hcd);
+ }
+
/* starting here, usbcore will pay attention to this root hub */
- retval = register_root_hub(hcd);
- if (retval != 0)
- goto err_register_root_hub;
+ if (!HCD_DEFER_RH_REGISTER(hcd)) {
+ retval = register_root_hub(hcd);
+ if (retval != 0)
+ goto err_register_root_hub;
- if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
- usb_hcd_poll_rh_status(hcd);
+ if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
+ usb_hcd_poll_rh_status(hcd);
+ }
return retval;
err_register_root_hub:
usb_stop_hcd(hcd);
+err_register_shared_root_hub:
+ if (!usb_hcd_is_primary_hcd(hcd) && shared_hcd && HCD_DEFER_RH_REGISTER(shared_hcd))
+ usb_stop_hcd(shared_hcd);
err_hcd_driver_start:
if (usb_hcd_is_primary_hcd(hcd) && hcd->irq > 0)
free_irq(irqnum, hcd);
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 548a028f2dab..2c1fc9212cf2 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -124,6 +124,7 @@ struct usb_hcd {
#define HCD_FLAG_RH_RUNNING 5 /* root hub is running? */
#define HCD_FLAG_DEAD 6 /* controller has died? */
#define HCD_FLAG_INTF_AUTHORIZED 7 /* authorize interfaces? */
+#define HCD_FLAG_DEFER_RH_REGISTER 8 /* Defer roothub registration */
/* The flags can be tested using these macros; they are likely to
* be slightly faster than test_bit().
@@ -134,6 +135,7 @@ struct usb_hcd {
#define HCD_WAKEUP_PENDING(hcd) ((hcd)->flags & (1U << HCD_FLAG_WAKEUP_PENDING))
#define HCD_RH_RUNNING(hcd) ((hcd)->flags & (1U << HCD_FLAG_RH_RUNNING))
#define HCD_DEAD(hcd) ((hcd)->flags & (1U << HCD_FLAG_DEAD))
+#define HCD_DEFER_RH_REGISTER(hcd) ((hcd)->flags & (1U << HCD_FLAG_DEFER_RH_REGISTER))
/*
* Specifies if interfaces are authorized by default
--
2.17.1
Set "HCD_FLAG_DEFER_RH_REGISTER" to hcd->flags in xhci_run() to defer
registering primary roothub in usb_add_hcd(). This will make sure both
primary roothub and secondary roothub will be registered along with the
second HCD. This is required for cold plugged USB devices to be detected
in certain PCIe USB cards (like Inateck USB card connected to AM64 EVM
or J7200 EVM).
Signed-off-by: Kishon Vijay Abraham I <[email protected]>
Suggested-by: Mathias Nyman <[email protected]>
Tested-by: Chris Chiu <[email protected]>
---
drivers/usb/host/xhci.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 3618070eba78..7176058c7f3e 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -692,6 +692,7 @@ int xhci_run(struct usb_hcd *hcd)
if (ret)
xhci_free_command(xhci, command);
}
+ set_bit(HCD_FLAG_DEFER_RH_REGISTER, &hcd->flags);
xhci_dbg_trace(xhci, trace_xhci_dbg_init,
"Finished xhci_run for USB2 roothub");
--
2.17.1
On 26.8.2021 14.14, Kishon Vijay Abraham I wrote:
> Set "HCD_FLAG_DEFER_RH_REGISTER" to hcd->flags in xhci_run() to defer
> registering primary roothub in usb_add_hcd(). This will make sure both
> primary roothub and secondary roothub will be registered along with the
> second HCD. This is required for cold plugged USB devices to be detected
> in certain PCIe USB cards (like Inateck USB card connected to AM64 EVM
> or J7200 EVM).
>
> Signed-off-by: Kishon Vijay Abraham I <[email protected]>
> Suggested-by: Mathias Nyman <[email protected]>
> Tested-by: Chris Chiu <[email protected]>
> ---
Acked-by: Mathias Nyman <[email protected]>
On 26.8.2021 14.14, Kishon Vijay Abraham I wrote:
> It has been observed with certain PCIe USB cards (like Inateck connected
> to AM64 EVM or J7200 EVM) that as soon as the primary roothub is
> registered, port status change is handled even before xHC is running
> leading to cold plug USB devices not detected. For such cases, registering
> both the root hubs along with the second HCD is required. Add support for
> deferring roothub registration in usb_add_hcd(), so that both primary and
> secondary roothubs are registered along with the second HCD.
>
> Signed-off-by: Kishon Vijay Abraham I <[email protected]>
> Suggested-by: Mathias Nyman <[email protected]>
> Tested-by: Chris Chiu <[email protected]>
Acked-by: Mathias Nyman <[email protected]>
On Thu, Aug 26, 2021 at 04:44:25PM +0530, Kishon Vijay Abraham I wrote:
> It has been observed with certain PCIe USB cards (like Inateck connected
> to AM64 EVM or J7200 EVM) that as soon as the primary roothub is
> registered, port status change is handled even before xHC is running
> leading to cold plug USB devices not detected. For such cases, registering
> both the root hubs along with the second HCD is required. Add support for
> deferring roothub registration in usb_add_hcd(), so that both primary and
> secondary roothubs are registered along with the second HCD.
>
> Signed-off-by: Kishon Vijay Abraham I <[email protected]>
> Suggested-by: Mathias Nyman <[email protected]>
> Tested-by: Chris Chiu <[email protected]>
> ---
I should have noticed this problem before...
> drivers/usb/core/hcd.c | 27 ++++++++++++++++++++++-----
> include/linux/usb/hcd.h | 2 ++
> 2 files changed, 24 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index 00d35fe1fef0..64fdfc6692c2 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -2795,6 +2795,7 @@ int usb_add_hcd(struct usb_hcd *hcd,
> {
> int retval;
> struct usb_device *rhdev;
> + struct usb_hcd *shared_hcd;
>
> if (!hcd->skip_phy_initialization && usb_hcd_is_primary_hcd(hcd)) {
> hcd->phy_roothub = usb_phy_roothub_alloc(hcd->self.sysdev);
> @@ -2955,18 +2956,34 @@ int usb_add_hcd(struct usb_hcd *hcd,
> goto err_hcd_driver_start;
> }
>
> + /* starting here, usbcore will pay attention to the shared HCD roothub */
> + shared_hcd = hcd->shared_hcd;
> + if (!usb_hcd_is_primary_hcd(hcd) && shared_hcd && HCD_DEFER_RH_REGISTER(shared_hcd)) {
> + retval = register_root_hub(shared_hcd);
> + if (retval != 0)
> + goto err_register_shared_root_hub;
> +
> + if (shared_hcd->uses_new_polling && HCD_POLL_RH(shared_hcd))
> + usb_hcd_poll_rh_status(shared_hcd);
> + }
> +
> /* starting here, usbcore will pay attention to this root hub */
> - retval = register_root_hub(hcd);
> - if (retval != 0)
> - goto err_register_root_hub;
> + if (!HCD_DEFER_RH_REGISTER(hcd)) {
> + retval = register_root_hub(hcd);
> + if (retval != 0)
> + goto err_register_root_hub;
>
> - if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
> - usb_hcd_poll_rh_status(hcd);
> + if (hcd->uses_new_polling && HCD_POLL_RH(hcd))
> + usb_hcd_poll_rh_status(hcd);
> + }
>
> return retval;
>
> err_register_root_hub:
> usb_stop_hcd(hcd);
> +err_register_shared_root_hub:
> + if (!usb_hcd_is_primary_hcd(hcd) && shared_hcd && HCD_DEFER_RH_REGISTER(shared_hcd))
> + usb_stop_hcd(shared_hcd);
This was added in the wrong place. It needs to come before the
usb_stop_hcd(hcd) call, because usb_start_hcd(hcd) was run before we failed to
register the shared hcd's root hub.
Furthermore, I don't think we need to stop the shared hcd at all. At this
point, the usb_add_hcd() call for the shared hcd has already returned
successfully. The usb_stop_hcd(shared_hcd) callback will be made automatically
when the shared hcd is unregistered later on, after this function returns an
error.
Come to think of it, don't we also need to modify the usb_disconnect(&rhdev)
call in usb_remove_hcd() to handle the case where the root hub wasn't
registered in the first place because it was deferred? At the very least, we
should test the hcd's rh_registered flag before trying to unregister the root
hub.
Alan Stern
> err_hcd_driver_start:
> if (usb_hcd_is_primary_hcd(hcd) && hcd->irq > 0)
> free_irq(irqnum, hcd);
> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
> index 548a028f2dab..2c1fc9212cf2 100644
> --- a/include/linux/usb/hcd.h
> +++ b/include/linux/usb/hcd.h
> @@ -124,6 +124,7 @@ struct usb_hcd {
> #define HCD_FLAG_RH_RUNNING 5 /* root hub is running? */
> #define HCD_FLAG_DEAD 6 /* controller has died? */
> #define HCD_FLAG_INTF_AUTHORIZED 7 /* authorize interfaces? */
> +#define HCD_FLAG_DEFER_RH_REGISTER 8 /* Defer roothub registration */
>
> /* The flags can be tested using these macros; they are likely to
> * be slightly faster than test_bit().
> @@ -134,6 +135,7 @@ struct usb_hcd {
> #define HCD_WAKEUP_PENDING(hcd) ((hcd)->flags & (1U << HCD_FLAG_WAKEUP_PENDING))
> #define HCD_RH_RUNNING(hcd) ((hcd)->flags & (1U << HCD_FLAG_RH_RUNNING))
> #define HCD_DEAD(hcd) ((hcd)->flags & (1U << HCD_FLAG_DEAD))
> +#define HCD_DEFER_RH_REGISTER(hcd) ((hcd)->flags & (1U << HCD_FLAG_DEFER_RH_REGISTER))
>
> /*
> * Specifies if interfaces are authorized by default
> --
> 2.17.1
>